Mahaut (Crequy) de Boulogne (abt. 895)

There are some cousin-marriages between de Guînes, Boulogne, Flanders etc which complicate placement(s) and identification(s) of this woman's descendants. Is anybody expert in these inter-connected families? Concerned that previous researchers may have ruled out certain connections presuming consanguity is not kosher, when in fact, it was common for a variety of reasons.

Here is one example: https://fr.wikipedia.org/wiki/Rodolphe_Ier_de_Gu%C3%AEnes

«Il épousa v.1010, Rosella (°v.995 †?), fille d'un comte de Saint-Pol, peut-être d'Hugues II de Saint-Pol. Les auteurs divergent sur la signification du nom de son épouse : pour les uns, Roselle provient de la couleur de son teint ; pour les autres, elle a été ainsi nommé en référence à Rozala, épouse d'Arnoul II de Flandre2. Elle épouse Rodolphe bien qu'ils aient été cousins au 3e degré, car Rodolphe était petit-fils d'Arnoul II comte de Boulogne, qui était lui-même frère d'Hugues Ier de Saint-Pol, grand-père de Rosella1.»

I realize this is "just" Wikipedia, got it; curator of that page cites (but I have not read) this 1632 source:

• Duchesne, André, Histoire généalogique des maisons de Guines, d'Ardres, de Gand et de Coucy et de quelques autres familles

I've merely "bumped into" these folks & and not actively working on them. I come to this profile / family group, working backwards from a certain Guy de Guînes, briefly ~13th count of Forez during the Crusades (circa ~1110) and transition of Forez from the house of Albon to Forez (d'Albon-de-Forez cadet line).

I'm trying to ascertain why -- through what marriage or logic -- Forez ended up (briefly) in the hands of Guy de Guînes; and what the relationship is or may be (if any) between that Guy (i.e. Guigues) de Guînes, and the subsequent very long run of ~10 Guigues in Forez and Lyon etc. The latter are lineal for my kids, and a zillion living descendants of de La Tour et al pioneers of Acadia; and broadly speaking, most of these families end up in Jerusalem centuries before Acadia, which is interesting history. So I'd like to map out the causaulities of who/what/where/why/when to the extent possible. This forces me to follow the titles and lands moving between families (including possibly this one) in addition to names and genealogy.

Separately,

If any experts in this region have strong feelings about when Danish names become French or Flemish names, eg Arnulf --> Arnoul, please advise. By when I mean, when should we make that change here on Wikitree, according to their customs by generation regardless of what modern researchers have back-propagated. Perhaps a better way to ask this question is what year/generation would we label a hypothetical man called GOFRID SIGURDSSON, jarl of nothing, mere warlord-raider of (the imaginary town) Ville, as Godfrey de Ville, comte en [foo] etc?

This is further complicated by the concept of LNAB being used by convention to encode names not actually given at birth, and some of our name syntax policy confusing in essence everybody except us 😉 e.g. a Dane simply named GOFRID SIGURDSSON in reality might by policy actually have a profile named "Godfrey (Godfrid) "comte en Ville" (Ville) de Ville formerly Ville" on WikiTree. Which of course is used nowhere else. So, as we work through these profiles and their connections and numbering etc, to reiterate: when ought we switch from emigrant-name-culture to immigrant-name-culture, in essence? (Options: Before or after the invasion? Titling? Inheritance of the holding, such that it becomes a defacto family name? Or later, when we have a surviving primary source artifact in latin i.e. perhaps generations later?)

Cheers,

Potential duplicate De Crequy-13

father of Mahaut:

Arnoul II «Le Borgne» +X 937 au service d’Arnoul «Le Vieil», comte de Flandres, seigneur de Créquy ép. Valburge d’Argouins ° 908